[time-nuts] WWVB Chronverter update progress

[paul swed]

Have to look at what oscillators and crystals I have then a divide.
Thats old style and most likely the junk box has everything.
Have to look in my box of tricks as I built several chains for the
de-psk-er experiments.
Have to agree on the micro the chronverter uses a pIC 12F64 as I recall and
it has quite a nice set of dividers in it. Just not an external crystal
input so a better oscillator can be used. Getting lazy these days.
I have some number of tcxos from a company called vectron. Several cards of
each. Can't imagine how I came by those.
:-) Believe the lowest freq was 12 MHz.
Regards
Paul.


On Sat, Aug 25, 2018 at 8:07 PM, Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> A pretty simple modest Q tuned circuit on the output of a gate will turn
> the square wave
> into a sine. Not much to it since there are a lot of power supply
> components out there that
> work fine at 60 KHz. In order to get a stable 60KHz, a divider is the way
> to go. I’d probably
> use one that’s built into an MCU as part of a timer or something similar.
>
> Bob
>
> > On Aug 25, 2018, at 7:00 PM, paul swed <paulswedb at gmail.com> wrote:
> >
> > Bob The generator sig is 60 Khz sinewave.but as a I build up a divider
> > chain and such your idea makes great sense.
> > Then filter to 60 KHz.
> > But I see the issue with the Chronverter carrier its 120-150 Hz high.
> > Bounces around a fair amount.
> > There could be a secondary issue in that the carrier may not actually be
> > phase stable.
> > It really doesn't matter as for the Truetimes and Spectracoms its simply
> > not good enough.
> > I still need to try the cheapy clocks as that is what it was intended
> for.
> > Not throwing stones as so much of what it does saves me a bunch of coding
> > and doing exactly what Dave did.
> > Regards
> > Paul
> > WB8TSL
> >
> > On Sat, Aug 25, 2018 at 5:31 PM, Bob kb8tq <kb8tq at n1k.org> wrote:
> >
> >> Hi
> >>
> >> You can do the 14 db deep modulation with a tristate gate and a pair of
> >> resistors.
> >> Ground the input and feed the “modulation” signal to the tristate
> control.
> >>
> >> Bob
> >>
> >>> On Aug 25, 2018, at 4:35 PM, paul swed <paulswedb at gmail.com> wrote:
> >>>
> >>> From the earlier threads OOK modulation does not work for high end
> clocks
> >>> like spectracoms and truetimes. Have not tried it on the cheapy clocks
> >> yet.
> >>>
> >>> I added an external modulator. A dg419 analog switch and then with a
> few
> >>> resistors added DC offset and anttenuation so that the carrier drops by
> >> -14
> >>> db per the wwvb spec. The logic control is driven from the chronverter
> >> and
> >>> it totally works. Spectracom Netclock 2 locked up in the normal time.
> >>> There are far better modern single supply analog gates that will work.
> >> Just
> >>> did not have any.
> >>>
> >>> The 60 KHz carrier is supplied by a fluke 6060 generator. This
> eliminates
> >>> any chance of being off frequency and is not the long term answer.
> >>>
> >>> The chronverter actually uses a dallas semiconductor clock chip thats
> >>> reasonably accurate.(dangerous to say on time-nuts) So that even if you
> >> do
> >>> not add the GPS receiver it will run quite some time correctly after
> >>> setting the time.
> >>>
> >>> Chronverter draws 6 ma from a 5 V supply. I always like low power.
> >>>
> >>> All in all a very nice answer to what do we do if WWVB goes away.
> >>> As mentioned it handles timezones and DST and you can change DST if
> those
> >>> silly politicians screw with it again.
> >>>
> >>> Speculation
> >>> The chronverter actually puts out carriers for the popular LF stations
> >>> along with the time codes for them.
> >>>
> >>> Though the modulator allows quality clocks to lock I speculate the
> >>> frequency from the chronverter is not tight enough. All of these clocks
> >>> have very sharp crystal filters in them. 10 Hz. Plan to measure the
> >> output
> >>> of the chronverter see what the 60 KHz is actually at. Though listening
> >> on
> >>> a HP3586 receiver it appears pretty close to frequency maybe its just
> not
> >>> good enough. Or the fact is OOK modulation does not work because it
> gaps
> >>> the PLL in these clocks.
> >>>
> >>> Next steps
> >>>
> >>>  - Determine and lay to rest the OOK/need for external modulator.
> >>>  - Power amplifier and loopstick transmitting antenna staying at or
> >> below
> >>>  30uv at 30 meters.
> >>>  - Integrate a neo6 GPS receiver in. (Seriously easy)
> >>>  -
> >>>  - Box it up.
> >>>
> >>> Have my eye on one of the Truetime DC468 units and the classy panelplex
> >>> display.
> >>>
> >>> Hope this helps those of you concerned with what to do should WWVB go
> >> away.
> >>> Regards
> >>> Paul
> >>> WB8TSL
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> >>
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